106 Electro-Magnetism, as a Moving Power, 



Art. YI. — On Electro-Magnetism, as a Moving Power; by 

 Chari.es G. Pagi:, M. D., Washington City, D. C. 



After the first successful magnetization of soft iron by the gal- 

 vanic current, and more especially on the announcement of Prof. 

 Henry's signal experiment, the suggestion naturally occurred to 

 every enquiring mind, cannot this immense attractive power, so 

 easily developed and controlled, be rendered available as a me- 

 chanical agent? The first successful step towards the attainment 

 of this object, of which we have any record, was made by Mr. 

 William Sturgeon, a distinguished philosopher of England. The 

 next original invention by which an independent motion was ob- 

 taiiied from electro-magnets, was the oscillating apparatus of Prof. 

 Henry, described in a previous No. of this Journal. The next 

 invention of any note, was that of Dr. Ritchie, now very well 

 known as Ritchie's revolving magnet. This ingenious and sim- 

 ple contrivance, will always be regarded as a superb philosophical 

 apparatus. It does not exhibit that astonishing rapidity of rota- 

 tion, as if its poles were changed by the use of solid conductors^ 

 but as an instrument is more pleasing, as it shows at the same 

 time the magnetic rotation, the vivid sparks, and in the dark .a 

 beautiful optical illusion. Some time after the announcement of 

 this instrument in this country, Mr. Davenport of Vermont pub- 

 lished in this Journal a partial description of an electro-magnetic 

 engine of considerable power. It appeared that Mr. Davenport 

 had for a long time been occupied in the subject, and was not 

 aware of what had been previously effected by others. Some 

 time prior also to this period, some interesting experiments were 

 described in this Journal, by Dr. Edmondson of Baltimore, and, 

 indeed, this gentleman appears to have been the first in this coun- 

 try who produced a rotary electro-magnetic machine. Since the 

 announcement of Mr. Davenport's invention, the innumerable ex- 

 periments which have been performed in this country, in Eng- 

 land, on the continent of Europe, and even in the East Indies, 

 have all contributed to prove that the smallest engines which 

 have been made, have had by far the greatest proportionate power. 

 Since I first gave the subject any attention, I have had sixteen 

 different models constructed, each involving distinct principles. 

 From all these experiments the inference is still the same, viz. 



